In vitro and in vivo degradation behavior of Mg–2Sr–Ca and Mg–2Sr–Zn alloys

Magnesium alloys with integration of degradability and good mechanical performance are desired for orthopedic implants. In this paper, Mg–2Sr–Ca and Mg–2Sr–Zn alloys were prepared and the degradation as well as the bone response were investigated. Compared with the binary Mg–2Sr alloys, the addition of Ca and Zn improved the in vitro and in vivo corrosion resistance. Mg–2Sr–Ca and Mg–2Sr–Zn alloys exhibited more uniform corrosion and maintained the configuration of the implants 4 weeks post-implantation. The in vivo corrosion rates were 0.85 mm/yr for Mg–2Sr–Zn and 1.10 mm/yr for Mg–2Sr–Ca in comparison with 1.37 mm/yr for Mg–2Sr. The in vitro cell tests indicated that Mg–2Sr–Ca and Mg–2Sr–Zn alloys exhibited higher MG63 cell viability than Mg–2Sr alloy. Furthermore, these two alloys can promote the mineralization and new bone formation without inducing any significant adverse effects and this sound osteogenic properties suggest its attractive clinical potential.